Electric switch



May 9 1939- I A. clANcl-n 2,157,114

ELECTRIC swI'TCH I Filed NOV. l27, 1935 2 Sheets-Sheet l Fig. 1 2

Figi

May 9, 1939.

A. clANcHl ELECTRIC SWITCH Filed NOV. 27, 1955 2 Sheets--Sheei'l 2 Patented May 9, 1939 PATIENT ori-lcs 2,151,114. y momo swrron Alfredo einem,

London, England Application November 27, 1935, Serial No. 51,962 In Great Britain November 27, 1934 20 Claims.

This invention relates to mercury switches of the kind in which contact is made or broken as the result o! the displacement of mercury by a magnetic armature which is moved electro- '5 magnetically.

According to the invention the armature in a switch of this kind is inthe form ot or forms partofavesselcontainingpartofthemercuryso that when the armature is moved the mercury in l the armature moves also but which has an opening which tablishes communication between the mercury in the vessel and that outside it so as to allow the level of mercury inside the vessel to reach that of the outside without preventing the l level of mercury in said vessel from moving with said armature to make or break vcontact with said second contact member when said armature moves. The armature could itself constitute the vessel or it could co-operate. with the wall of the ,'20 vessel containing it and the mercury so that a vessel capable of containing mercury is 'formed between them. The opening could be uncontrolledaxd small enough to cause the mercury in the vessel to move when the armature moves. In

that case this opening eventually allows the mercury to ilow back into the vessel and equalise.

the levels inside and outside it if the armature is retained in its displaced position for long enough. The switch then acts as a time switch. If this action is not desired the switch could, according to a further feature of the invention, be provided with a valve for closing the opening. Thus, the valve could be astationary member against which the opening is held so as substantially to close it when the armature is in the displaced position,

or the valve could be carried in the amature itself. It will be seen that the working of the switch according to the invention cannot be upset if -the switch is tilted or moved about, for example during transport, for the mercury will always come to the proper level both inside and outside the vessel due tothe presence of the opening.

In order that the invention may be clearly un` derstood `and readily carried into eifect, it will now be described in greater detail with reference to the examples illustrated in the accompanying diagrammatic drawings inwhichz- Figs. 1 and 2 are longitudinal sectional views in a switch according to the invention.

Referring rst to the example illustrated in Fig. 1, i is the closed receptacle of the switch which contains the iron armature V2 and the mercury I. 4 is the solenoid which, when energised, draws the armature 2 down into the body of mercury. This particular example of switch has three contact members, one i projecting from the. Vtop down into the mercury within the tubular armature 2, one 6 projecting into vthe body of mercury outside the armature at the bottom, and one 1 arranged in a side branch of the vessel l and at a height above the normal level of mercury. The armature 2. is in the form of a vessel, that is to say its lower end is closed, except for an opening 8. When the solenoid 4 is deenergised. the armature 2 iioats in the mercury and occupies the position shown in Fig. l. In this position there is free communication between tlie mercury 2 in the armature vessel 2 and the 'body of mercury 3 outside it so that the levels of the mercury ,inside and outside the armature 2 are the same, as shown. ,There is electrical contact between the contacts 5 and 6 through the mercury in this position. When the armature 2 is drawn down by the energlsed solenoid 4, it takes the mercury 3 inside it down with it and at the same time raises the level of the general body of mercury 3 to suchan extent that this mercury ilows into the side limb and establishes contact with the contact 1. The lowering of the armature 2 has, however, brought the mercury within it out of contact with the contact 5, Thus, the result is that contact between 5 and is broken and contact between 6 and 1 established. Ii' no means were provided to prevent it, however, mercury would iiow from the general body of mercury 3 into the vessel 2 while it was being held down by the solenoid 4 and eventually equalise the two levels. The level would not be quite the same as the original level, due to the greater immersion of the armature, but -it could be arranged to reach the contact 5 and thus re-establish contact between 4 and 5 while breaking that between 6 and 1, the solenoid 4 still remaining energised. Thus, the switch would act as a time switch. If desired, however, and as illustrated, the openingB could be closed by a valve when the armatureis drawn into the "down position so as to prevent the ilow of mercury back into the vessel 2 while the armaturelsin that position. This valve might consist of an enlarged head 9 on the contact 6, the opening being merely held against this head due to the action of the armature. Although this switch has ybeen described as having a side contact 1, it'is-to'\be` understood that it could if desired be made without this contact when it would act simply as a make-and-break switch for a single circuit. It will, of course, be understood that the opening 8 is suiiiciently small as to prevent mercury flowing from the body of.

forming the receptacle I. The reservoir 20 is secured to this extended insulation by means of radial webs 2I. A small opening 22 is provided at the bottom of the reservoir 20. When the armature is in the oating condition illustrated, the level of mercury -in the armature 2 is slightly above the top edge of the reservoir 20 which is then filled with mercury. When the armature 2 is drawn down on energizing of the solenoid 4, the level of mercury in the armature 2 falls to below the bottom of the reservoir 20. Contact between contact 5 and the mercury is not, however, broken because a certain quantity of mercury is left behind in the reservoir 20 and iiows out through the hole 22 in a thin stream which gives electrical connection between contact 5 and the mercury 3' and therefore :with 3 until the reservoir is empty when contact is broken. When the armature 2 rises, mercury does not immediately fill the reservoir 20 through the hole 22 which is too small for that purpose. However, mercury ilows over the top edge of the reservoir 20 to fill it again. The solenoid 4 is connected in series with the contact 6 and the remaining leads of the solenoid 4 and contact 5 are connected to the source of operating current so that the armature 2 automatically moves up and down as long as current is supplied. 'Ihe provision of the reservoir 20 prevents the up and down movement of the armature 2 from being too rapid and in fact the frequency with which the armature moves up and down can be made different by employing different sizes of reservoir.

In the switch of Figs. 2 and 3, in which again the corresponding parts are given the same reference numerals as in Fig. 1, the tubular iron armature 2 carries a valve which moves to control an opening at the bottom. The normal condition of the switch is illustrated, that is a condition in which the surrounding solenoid is not energized, the iron armature 2 floating in the mer-,j cury. The valve 9 is a ball valve and its seat is'.

the bottoni of a steatite or other insulating tubular liner I in the armature 2. The valve 9 is held ,on its seat I0 in the armature 2 in the normal condition of the switch by the lower end of the contact 5 which comes into contact with the top of the `valve just before the armature 2 reaches its uppermost position. In this position there is freecommunication between the body of mercury 3 andthe mercury 3 within the armature 2. When the solenoid is energized the armature 2 is drawn down. After it has made a small movement the valve 9 closes against its seating I0 so that the armature 2 then becomes examples described above, it need not do so.

lower contact 6 and the side contact 1, while it is broken between the upper contact 5 and the lower contact 6. 'I'he valve 9 remains against its .seating I0 while the armature is held in the down position because of the tendency of the f valve 9 to float in the mercury so that the original between the mercury in the armature 2 and that outside it and assist in the electrical operation of the switch. The switch of Fig. 2 is carried on a plate II which is mounted on a base plate I2 by means of a' spindle I3 so as to be capable of rotation on it about a horizontal axis. As a result theswitch may be tilted to vary the time which elapses before contact is established with the side contact 1. The base plate I2 is provided with screw holes I4 by means of which the switch may be secured to a vertical surface such as that of a wall. By tilting the switch far enough in one direction or the other, the contact I could be put entirely out of action or rendered continuously in contact with the mercury 3.

Figs. 4 and 5 illustrate the construction of a tubular armature suitable for use in the switch of Figs. 3 and 4. The armature 2 is made by bending an appropriately-formed sheet of iron into a substantially cylindrical form with its adjacent edges not quite meeting. The top and bottom edges are provided with projections, some of which I4 are bent outwards, the others I5 being bent inwards. 'I'he projections I4 serve to guide the armature on the wall of the receptacle I. The upper projections I5 serve to retain in place the steatite tubular liner I0. The lower edge of this liner I0 rests on a spring -ring I6 which in turn rests on an annular ridge4 I1 pressed up in the metal of the armature 2. The' spring ring I6 serves as'the seating for the ball valve 9, which is not shown in Fig. 5, but which is retained in position by the lower bent-in projections I5. The ends I6' of the spring ring I6 -do not quite meet and the gap forms a by-pass for the valve 9 so that mercury would slowly flow back into the armature 2, even though the armature is held down, and ultimately restore substantially the original state of affairs. The gap would not be large enough to enable mercury to enter or leave the armature fast enough to retain unchanged the level in it. Instead of employing a gapped spring ring I6, however, the lower edge of the liner Ill could be employed as the valve seat and the by-pass provided by notching the lower edge of the liner. A at, cone or other valve could be employed instead of a ball valve.

It is to be understood that although the armature is dravm down into the mercury in the It could be deeply immersed in its normal position with the solenoid de-energized as by beingl weighted or held down by a spring and raised by the solenoid when it is energized. In that case the mercury inside the vessel would be raised to make contact with the upper contact. Moreover,

the hole 22 in the reservoir 2l could be controlled by a valve arranged to close when the mercury v 'endeavours to enter the hole from below but to of magnetic material, said armature forming at least part oi a vessel receiving part of the conducting liquid, at least two contact members cooperating with the conducting liquid, magnetic means acting on said amature to vary its extent of immersion in said conducting liquid and therefore the level oi the conducting liquide to cause said conducting liquid to make or break electrical connection between at least two of said contact members, said vessel having an opening establishing communication between the conducting liquid inside and outsidesaid vessel, and a valve closing said opening at least partially when said armature moves from the position it occupies when the magnetic means is inoperative.

2. An electric switch comprising a receptacle containing4 mercury and an armature of magnetic material, said armature forming at least part of a vessel receiving part ofthe mercury, two contact members co-operating with the mercury, electromagnetic means acting on said armature to vary its extent oi immersion in said mercury and therefore the level of the mercury to cause said mercury to make or break electrical connection between said contact members, said vessel having an opening establishing communication between the mercury inside and outside said vessel, and a valve carried by said armature and controlling said opening, said valve being open in the position occupied by said armature when said electromagnetic means is inoperative but closing when said armature is-moved from that position so as to cause relative .movement between the levels of mercury inside and outside said vessel, and a bypass opening allowing y assage of mercury between the inside and ou oi said vessel to restore substantially the original condition'ofthe switch on said armature being retained in the displaced position.

3. An electric switch comprising a receptacle containing mercury and an armature of magnetic material, said armature forming atleast part of a vessel receiving part of the mercury, a contact member co-operating with the mercury, two iurther contact members one of which co-operates with the mercury in said vessel and the other with the mercury outside said vessel, magnetic means acting on said armature to vary its extent ofv immersion in the mercury, said vessel having an opening establishing -communication with the mercury insideand outside said vessel, said opening being small enough to ensure-that the level of the mercury insaid vvessel moves in the opposite direction tothe level of the mercury outside said vessel to cause said mercury to make electrical connection betweenv said first-mentioned contact member and one of said further contact members and to break electrical -connection between said first-mentioned contact and the other oi said further contact members, and a valve against which said opening is drawn-.so as to close it when said armature moves in one direction.

4. An electric switch comprising a receptacle containing mercury and an armature of magnetic material, saidarmature forming atleast part of a vessel receiving part of 'the mercury,

a contact member co-operating with the mercury, two further contact members one of which cooperates with the mercury in said vessel and the other with the mercury outside said vessel, magnetic means acting on said armature to vary its extent of immersion in the mercury, said vessel having an opening establishing communicationwith the mercury inside and outside said vessel, and a valve carried by said armature and controlling said opening, said valve being in one position of said armature but closing when said armature is moved from said position so as to cause the level of mercury in said vessel to move in the opposite direction to the level of thel mercury outside said vessel to cause said mercury to make electrical connection between said first-mentioned contact member and one oi said further contact members and to break electrical connection between said first-mentioned contact memberrand the other oi said further contact members.

5. An electric switch comprising a receptacle containing mercury and an armature of magnetic material, said armature forming at least part of a vessel receiving part of the mercury, a contact member co-operating with the mercury, two further contact members one of which co-operates with the mercury in said vesseln and the other with the mercury outside said vessel, magnetic means acting on said armature to vary its extent of immersion in the mercury, said vessel having an opening establishing communication with the mercury inside and outside said vessel, and a valve carried by said armature and controlling said opening, said valve being open in one position of said armature but closing when said armature is moved from said position so as to cause the level ofy mercury in the vessel to move in the Vopposite direction to the level of the mercury outside said vessel to cause said mercury to make electrical connection between said ilrst-mentioned contact member and one of said further contact members andto break electrical connection between said first-mentioned contact mem-- ber and the other of said further contact members, and a by-pass opening allowing passage of mercury between the outside and the inside of said vessel to restore substantially the original condition ofthe switch on said armature being retained in the displaced position.

6. An electric switch comprising a receptacle containing a conducting liquid and an armature of magnetic material, said armature forming at least part o! a vessel receiving part of the conducting iiquid and normally floating in said conducting liquid, a contact member in continuous electrical contact with the conducting liquid, a second contact member normally dipping into the `conducting liquid in said vessel, a third contact member disposed above the normal level of the -conducting liquid outside saidvessel, magnetic ducting liquid inside said aessel leaving said secondi` contact member and the conducting liquid outside said vessel reaching said third contact member when the extent of immersion of said armature is increased by said magnetic means,

and a valve against which said opening is drawn so as to close it when said armature is moved by said magnetic means.

'7. An electric switch comprising a receptacle containing mercury and an armature of magnetic material, said armature forming at least part of a vessel receiving part o! the mercury and normally floating in` said mercury, a contact member in continuous electrical contact with the mercury, a second contact member normally dipping into the mercury in said vessel, a third contact member disposed above the normal level of the mercury outside said vessel, magnetic means acting on said armature to increase its extent of immersion in the mercury, said vessel having an opening establishing communication between. the m'ercury inside and outside said vessel, and a valve carried by said armature and controlling said opening, said valve being open in the oating position of said armature, but closing when said armature is moved from said position so as to cause the level of mercury in said vessel to move in the opposite direction to the level of the mercuryoutside said vessel to cause said mercury to leave said second contact member and to reach said third contact member.

8. An electric switch comprising a receptacle containing mercury and an armature of magnetic material, said armature forming at least part of a vessel receiving part of the mercury and floating in said'mercury, a contact member in permanent electrical contact with theV mercury, a second contact member normally dipping into the mercury in said vessel, a third contact member disposed above the normal level of the mercury outside said vessel, magnetic means acting on said armature to increase its extent o1 immersion in the mercury, said vessel having an opening establishing communication between the mercury inside and outside said vessel, and a valve carried by said armature and controlling said opening, said valve being open in the iioating position of said armature but closing when said armature is moved fromsaid position so as to cause the level of mercury in the vessel to move in the opposite direction to the level of the mercury outside said Vessel to cause said mercury to leave said second contact member and 'to reach said third contact member, and a by-pass opening allowing passage of mercury between the inside and the outside of said vessel to restore substantially the original condition of the switch on said armature being position.

9. An electric switch comprising a receptacle containing a conducting liquid and an armature oi magnetic material, at least two contact members, magnetic means acting on said armature to vary its extent of immersion in said conducting liquid to change the level of said conducting retained in the displaced liquid to break or make electrical connection be' I for a time after the level of the conducting liquid Y has changed.

10. An electric switch comprising a receptacle containing a conducting liquid and an armature of magnetic material, atleast two contact members, magnetic means acting on said armature to vary its extent of immersion in'said conducting liquid to change the. level of said conducting liquid to break or make electrical connection between said contact members, and means for tilting said receptacle to alter the levelv of said conducting liquid relative to at least oneoi said contact members.

11. An electric switch comprising a receptacle containing a conducting liquid and an armature of magnetic material, said armature forming at least part of a vessel receiving part of the conducting liquid, at least two contact members cooperating with the conducting liquid, magnetic means acting on said\armature to vary its extent of immersion in said conducting liquid and therefore the level of the conducting liquid to cause said conducting liquid to make or break electrical connection between at least two of said contact members, said vessel having an opening establishing communication between the conducting liquid inside and outside said vessel, a Valve closing said opening at least partially when said armature moves in one direction, and means for tilting said .receptacle to alter the normal level of said conducting liquid relative to at least one of `said contact members.

12. An electric switch comprising a receptacle containing a conducting liquid and a tubular armature of magnetic material, said armature receiving part of the conducting liquid, at least two contact members co-operating with the conducting liquid, magnetic means acting on said armature to vary its extent of immersion in said conducting liquid and therefore the level of the conducting liquid to cause said conducting liquid Ato make or break electrical connection between at least two of said contact members, a liner of insulating material in said tubular armature, saidl ing at the bottom of saidliner at least partially when said armature moves in one direction.

13. An electric switch comprising a receptacle containing a conducting liquid and an armatureV of magnetic material, said armature forming at least part of a vessel receiving part of the conducting fiuid, at least two contact members cooperating with the conducting fluid, magnetic means acting on said armature to Vary its extent of immersion in said conducting fluid, said vessel having an opening establishing communication between the inside and outside of said vessel, a valve closing said opening at least partially to produce a difference between the levels .of the conducting fluid inside and outside said vessel when said armature moves in one direction, causing said conducting fluid to make or break electrical connection between at least two of said contact members, and opening when'said armature moves in the other direction.

-14. An-electric switch comprising a receptacle containing mercury and an armature of mag netic material, said armature forming at least part of a vessel receiving part of the mercury, at least two contact members cooperating with the mercury, magnetic means acting on said armature to vary its extent of immersion insaid mercury, said vessel having an opening establishing communication between the inside and outside of said vessel, 'a valve closing said opening to produce a diierence between the levels of the mercury inside and outside said vessel when said armature moves in one direction, causing said mercury to make or break electrical connection between at least two of said contact members, and being open when said armature moves in the other direction, and an opening bypassing said valve when it is closed.

15. An electric 'switch comprising a receptacle containing a conducting liquid, a vessel receiving part of said conducting liquid, at least two contact members cooperating with said conducting liquid, said vessel having an opening establishing communication between it and the conducting, liquid in said receptacle, magnetic means for causing conducting liquid to pass through said opening to produce a diilerenec between the levels of the conducting liquid inside and outside said vessel and cause said ,conducting liquid to make or break electrical connection between at least two of said 4contact members, and a valve being open when the conducting liquid passes through said opening in one direction and being closed at least partially when it tends to pass through in the other.

16. An electric switch comprising a receptacle containing mercury and an armature of magnetic material, said armature forming at least part of a vessel receiving part of the mercury, two contact members cooperating with the mercury, magnetic means acting on said armature to vary its extent of immersion in the mercury, said vessel having an opening establishing communication with the mercury inside and outside said Vessel, and a valve carried by said armature and co'ntrolling said opening, said valve tending to close said opening due to its buoyancy, means for holding said valve away from said opening when said valve is in one position but allowing said valve to close when said amature is moved from said position so as to cause the level of mercury in the vessel to move in the opposite direction to the level of the mercury outside said vessel and cause said mercury to make or break electrical connection between said contact members.

17. An electric switch comprising a receptacle containing a conducting liquid and an armature of magnetic material, said armature forming at least part of a vessel receiving part of the conducting liquid, at least two contact members. cooperating with the conducting liquid, magnetic means acting on said armature to vary its extent of immersion in said conducting liquid, to cause said conducting liquid to make or break electrical connection between at least two of said contact members, said vessel having an opening establishing communication between the inside and outside of said vessel, and a valve controlling said opening.

18. An. electric switch comprising a receptacle containing a conducting liquid and an armature of magnetic material in said conducting liquid, said armature forming at least part of a vessel receiving part of the conducting liquid, at least two contact members co-operating with the conducting liquid, magnetic'means acting on saidv armature to move it from one position to another, thus varying its extent of immersion in said conducting liquid to cause said conducting liquid to make or break electrical connection between at least two of said contact members, said vessel having an opening establishing communication between the inside and outside of said vessel, and a valve controlling said opening, said valve closing said opening at least partially in one of said positions of said armature and leaving it open in the other.

19. An electric switch comprising a receptacle containing a conducting liquid and an armature of magnetic material, said armature forming at least part of a vessel containing part of the conducting fluid, two. contact members co-operating with the conducting iluid, magnetic means acting on said armature to vary its extent of immersion in said conducting fluid and therefore the level of the conducting fluid to cause said conducting fluid to make or break electrical connection between said contact members, said vessel having an opening establishing communication between the conducting fluid inside and outside said vessel, and a valve carried by said armature and controlling said opening, said opening having a seat for said valve and said valve having a surface in contact with said seat and said valve being open in one position of said armature but closing when said armature is moved from that position so as to cause relative movement between the levels of conducting uid inside and outside said Vessel, and a by-pass opening at said seat allowing passage of conducting uid between the inside and outside of said vessel to restore substantially the original condition of the switch on said armature being retained in the displaced position.

20. The combination set forth in claim 18 wherein said valve for controlling the opening is carried by the armature and a seat is provided on the armature for said valve, whereby said'valve moves towards and away from said seat to cover and uncover said opening.

ALFREDO CIANCH'I. 

